Fig-mwahaha on Twitter: "In short, pressing Shift+2 using one key worked, but pressing Shift+2 using the numeric keypad key didn't. Curiously, the bug only happened on Windows, and not on a Mac.
File:Keyboard-Shift.svg - Wikimedia Commons
How to Fix Keyboard Shift Key Not Working in Windows 10/8/7 - YouTube
3 Ways to Switch Tabs with Your Keyboard on PC or Mac - wikiHow